/*
 * px-crypt.c
 *		Wrapper for various crypt algorithms.
 *
 * Copyright (c) 2001 Marko Kreen
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *	  notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *	  notice, this list of conditions and the following disclaimer in the
 *	  documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.	IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * contrib/pgcrypto/px-crypt.c
 */

#include "postgres.h"
#include "knl/knl_variable.h"

#include "px.h"
#include "px-crypt.h"

static char* run_crypt_des(const char* psw, const char* salt, char* buf, unsigned len)
{
    char* res = NULL;

    res = px_crypt_des(psw, salt);
    if (res == NULL || strlen(res) > len - 1)
        return NULL;
    strcpy(buf, res);
    return buf;
}

static char* run_crypt_md5(const char* psw, const char* salt, char* buf, unsigned len)
{
    char* res = NULL;

    res = px_crypt_md5(psw, salt, buf, len);
    return res;
}

static char* run_crypt_bf(const char* psw, const char* salt, char* buf, unsigned len)
{
    char* res = NULL;

    res = _crypt_blowfish_rn(psw, salt, buf, len);
    return res;
}

struct px_crypt_algo {
    char* id;
    unsigned id_len;
    char* (*crypt)(const char* psw, const char* salt, char* buf, unsigned len);
};

static const struct px_crypt_algo px_crypt_list[] = {{"$2a$", 4, run_crypt_bf},
    {"$2x$", 4, run_crypt_bf},
    {"$2$", 3, NULL}, /* N/A */
    {"$1$", 3, run_crypt_md5},
    {"_", 1, run_crypt_des},
    {"", 0, run_crypt_des},
    {NULL, 0, NULL}};

char* px_crypt(const char* psw, const char* salt, char* buf, unsigned len)
{
    const struct px_crypt_algo* c;

    for (c = px_crypt_list; c->id; c++) {
        if (!c->id_len)
            break;
        if (strncmp(salt, c->id, c->id_len) == 0)
            break;
    }

    if (c->crypt == NULL)
        return NULL;

    return c->crypt(psw, salt, buf, len);
}

/*
 * salt generators
 */

struct generator {
    char* name;
    char* (*gen)(unsigned long count, const char* input, int size, char* output, int output_size);
    int input_len;
    int def_rounds;
    int min_rounds;
    int max_rounds;
};

static struct generator gen_list[] = {{"des", _crypt_gensalt_traditional_rn, 2, 0, 0, 0},
    {"md5", _crypt_gensalt_md5_rn, 6, 0, 0, 0},
    {"xdes", _crypt_gensalt_extended_rn, 3, PX_XDES_ROUNDS, 1, 0xFFFFFF},
    {"bf", _crypt_gensalt_blowfish_rn, 16, PX_BF_ROUNDS, 4, 31},
    {NULL, NULL, 0, 0, 0, 0}};

int px_gen_salt(const char* salt_type, char* buf, int rounds)
{
    int res;
    struct generator* g;
    char* p = NULL;
    char rbuf[16];

    for (g = gen_list; g->name; g++)
        if (pg_strcasecmp(g->name, salt_type) == 0)
            break;

    if (g->name == NULL)
        return PXE_UNKNOWN_SALT_ALGO;

    if (g->def_rounds) {
        if (rounds == 0)
            rounds = g->def_rounds;

        if (rounds < g->min_rounds || rounds > g->max_rounds)
            return PXE_BAD_SALT_ROUNDS;
    }

    res = px_get_pseudo_random_bytes((uint8*)rbuf, g->input_len);
    if (res < 0)
        return res;

    p = g->gen(rounds, rbuf, g->input_len, buf, PX_MAX_SALT_LEN);
    memset(rbuf, 0, sizeof(rbuf));

    if (p == NULL)
        return PXE_BAD_SALT_ROUNDS;

    return strlen(p);
}
